# US 10,770,997 B2 · Power system > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,770,997 B2 - Document ID: US10770997B2 - Status: Granted - Kind: B2 - Application number: 16/401,570 - Filed: 2019-05-02 - Published: 2019-12-05 - Granted: 2020-09-08 - Earliest claimed: 2018-05-30 - Assignees: ROLLS-ROYCE plc; MTU Friedrichshafen GmbH; Mtu Onsite Energy GmbH - Applicants: ROLLS-ROYCE plc; Mtu Friedrichshafen GmbH; Mtu Onsite Energy GmbH - Inventors: Yang Shicong; Souvik Dasgupta; Michael Kreissl; Johannes Demharter; Amit K Gupta - Web page: https://patentgrep.com/patent/US10770997B2 ## CPC - H02P 9/102: {for limiting effects of transients} - G01R 25/00: Arrangements for measuring phase angle between a voltage and a current or between voltages or currents - H02K 19/36: Structural association of synchronous generators with auxiliary electric devices influencing the characteristic of the generator or controlling the generator, e.g. with impedances or switches - H02P 9/006: {Means for protecting the generator by using control (control effected upon generator excitation circuit to reduce harmful effects of overloads or transients H02P9/10)} - H02P 9/009: {Circuit arrangements for detecting rotor position} - G01R 31/343: {in operation} - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - G01R: MEASURING ELECTRIC VARIABLES; MEASURING MAGNETIC VARIABLES (indicating correct tuning of resonant circuits H03J3/12) - H02K: DYNAMO-ELECTRIC MACHINES (dynamo-electric relays H01H53/00; conversion of DC or AC input power into surge output power {H03K3/53}) ## Abstract A power system includes a synchronous electrical generator having a rotor driven by a shaft; a permanent magnet signaling generator, coupled to the shaft; and an angle computation unit configured to calculate a rotor angle or load angle based on a voltage from the permanent magnet signaling generator and a voltage from the synchronous electrical generator. ## Claims ### Claim 1 A power system, comprising: a synchronous electrical generator having a rotor driven by a shaft; a permanent magnet signalling generator, coupled to the shaft; and an angle computation unit configured to calculate a rotor angle and/or load angle based on a voltage from the permanent magnet signalling generator and a voltage from the synchronous electrical generator. ### Claim 2 (depends on 1) A power system (10) according to claim 1, wherein a number of magnetic poles in the permanent magnet signalling generator (21) is the same as a pole number of the rotor of the synchronous electrical generator (11). ### Claim 3 (depends on 1) A power system according to claim 1, wherein a number of phases of the permanent magnet signalling generator is the same as a number of phases in a stator of the synchronous electrical generator. ### Claim 4 (depends on 1) A power system according to claim 1, wherein magnetic poles of the permanent magnet signalling generator are aligned with magnetic poles of the synchronous electrical generator. ### Claim 5 (depends on 1) A power system according to claim 1, wherein the angle computation unit is configured to calculate the rotor angle or load angle in one or both of steady state and transient conditions. ### Claim 6 (depends on 1) A power system according to claim 1, wherein the angle computation unit is configured to: receive the voltage from the permanent magnet signal generator at a first resistor via a variable resistor, receive the voltage from the synchronous electrical generator at a second resistor, first ends of each of the first and second resistors being connected to each other and ground, adjust the value of the variable resistor until the voltages over the first resistor and over the second resistor are equal, and calculate an angle (δ) using the equation: δ = cos - 1 ⁡ ( V a , snl 2 + V a , pcc / t 2 - V ag 2 2 · V a , nsl ⁢ V a , pcc / t ) wherein Vag is the voltage between the un-earthed ends of the first and second resistors. ### Claim 7 (depends on 1) A power system according to claim 1, wherein the angle computation unit comprises a digital signal processor. ### Claim 8 (depends on 7) A power system according to claim 7, wherein the digital signal processor is configured to: receive a three phase voltage from the permanent magnet signal generator, and determine a voltage angle for the permanent magnet signal generator; receive a three phase voltage from the synchronous electrical generator, and determine a voltage angle for the synchronous electrical generator; and calculate an angle as the difference between the voltage angle for the permanent magnet signal generator and the voltage angle for the synchronous electrical generator. ### Claim 9 (depends on 1) A power system according to claim 1, wherein the electrical power output from the synchronous electrical generator is less than 30 MW. ### Claim 10 (depends on 1) A power system according to claim 1, wherein the voltage from the synchronous electrical generator is the voltage at the point of common coupling to a load attached to the synchronous electrical generator or the voltage at an output terminal of the synchronous electrical generator. ### Claim 11 A method of determining a rotor angle or load angle in a power system comprising synchronous electrical generator, the method comprising calculating the rotor angle or load angle based upon a voltage from a permanent magnet signalling generator coupled to a rotor shaft of the synchronous electrical generator. ### Claim 12 (depends on 11) A method of determining a rotor angle or load angle according to claim 11, wherein the power system is a power system. ### Claim 13 (depends on 11) A method of determining whether or not an out-of-step condition has occurred, the method comprising: determining a load angle and/or rotor angle of a generator system according to the method of claim 11; and determining whether or not an out-of-step condition has occurred depending upon the determined load angle and/or rotor angle. ### Claim 14 (depends on 11) A computer program that, when executed by a computing device, causes the computing device to determine a load angle and/or rotor angle in a power system according to the method of claim 11 and/or an out-of-step condition. ### Claim 15 (depends on 14) A computing device configured to determine a rotor angle in a power system and/or an out-of-step condition by executing the computing program of claim 14.